There is a frequent need to reverse aircraft on the ground, for example, from a parking space into which the aircraft drives forwards, or to maneuver the aircraft in a hangar or maintenance area. Common methods of reversing aircraft include pushback and powerback.
Pushback is carried out by attaching a tug to the nosewheel of an aircraft. The tug is a low-profile, self-powered vehicle which is usually manned by a driver. Conventionally, a tow-bar is used to attach the tug to the aircraft nose wheel to enable the tug to maneuver the aircraft. The use of tow-bar-less tugs is also known in the art, for example the TBL600 tug made by Douglas Equipment (UK), in which the nose wheel of the aircraft is picked up by the tug, enabling the tug to maneuver the aircraft. It is also known in the air to have unmanned tugs, for example those used by Air France. Tugs are commonly in short supply at airports and delays are often caused while aircraft wait for tugs. Additionally, the tug takes time to attach to the aircraft.
Powerback is the use of the turbine engines to reverse an aircraft. The turbine output is diverted so that the exhaust gases are blown forwards rather than backwards. This is known as reverse thrust, and is used to slow down the aircraft on landing. The use of reverse thrust to move the aircraft backwards is less common since it provides limited maneuverability, is noisy, and uses a large amount of fuel. Specifically, the powerback causes the jet exhaust to blow debris up from the ground, which often is then sucked into the intake. The fact that airlines have tried such a method in spite of the problems described is an indication of the value of being able to reverse aircraft from gates without the use of tugs.
A method for enabling an aircraft to enter and leave a parking space in which there is insufficient space to turn around is disclosed in the art.
DE1012260 to Kuesel discloses a rotating platform, having a linear conveyor belt within said platform, said conveyor belt having forward and reverse modes. The platform is located in an aircraft parking space and enables an aircraft driven onto it to be moved into position for unloading and loading of passengers, and then turned around before being driven off the platform.
This is expensive to install at airports and may not be large enough for all aircraft that may require it in the future.
Self-propelled undercarriage assemblies are known in the art. U.S. Pat. No. 3,711,043 to Cameron-Johnson discloses an aircraft drive wheel having a fluid-pressure-operated motor housed within the wheel and two planetary gear stages housed in a gear box outboard of the motor, the final drive being transmitted from a ring gear of the second gear stage, which is inboard of the first stage, to the wheel through an output drive quill coupled, through a disc-type clutch if desired, to a flanged final drive member surrounding the inner end of the gear box and bolted to the wheel.
U.S. Pat. No. 3,977,631 to Jenny discloses a wheel drive motor selectively coupled to an aircraft wheel through a rotatably mounted aircraft brake assembly in order to drive the wheels of an aircraft. The normally non-rotating stator portion of a conventional aircraft brake assembly is rotatably mounted about the wheel axle and is rotatably driven through a planetary gear system by the wheel drive motor.
A solution disclosed in WO2005/035358 discloses a mesh connected high phase order induction motor, situated in close proximity to, and preferably within, the nosegear. The mesh connection enables variable inductance so that the machine has a range of speed/torque profiles available.
European Patent No. 0 756 556 B1 to Giovanardi and Centofante discloses an aircraft having wheel driving means associated with at least one of the wheels of the landing gear. A motor powered by the auxiliary power unit of the aircraft is used to drive the wheels of the landing gear. The assembly comprises an electric or hydraulic motor in operative connection with a differential gear assembly, each wheel being mounted on an axle in forward operative connection with a respective half-shaft of the differential gear through a free wheel mechanism.
All of the solutions mentioned above require extra space to be occupied close to the undercarriage wheel, requiring extra space in the bay into which the undercarriage retracts. Space in this area is severely restricted. The shape and volume of the bay into which the undercarriage wheel retracts is of fixed size and cannot easily be altered. Further, using a bigger wheel and a bigger tire, in order to house a motor powerful enough to move the plane unassisted, will increase the mass of that part of the undercarriage, which may have deleterious effects on the balance and handling of the aircraft. Thus, installation of any of these motors requires serious modification of aircraft and as such they have not been widely used. Therefore, improved airport procedures and methods associated with such equipment have not been developed.
Motors providing high torque at low speeds are known in the art. Specifically, such motors are known that are designed for the purpose of propelling aircraft on the ground.
In WO05112584, Edelson discloses a motor-generator machine comprising a slotless AC induction motor. The motor disclosed therein is an AC induction machine comprising an external electrical member attached to a supporting frame and an internal electrical member attached to a supporting core; one or both supports are slotless, and the electrical member attached thereto comprises a number of surface mounted conductor bars separated from one another by suitable insulation. An airgap features between the magnetic portions of core and frame. Electrical members perform the usual functions of rotor and stator but are not limited in position by the present invention to either role. The stator comprises at least three different electrical phases supplied with electrical power by an inverter. The rotor has a standard winding configuration, and the rotor support permits axial rotation.
In WO2006/002207, Edelson discloses a motor-generator machine comprising a high phase order AC machine with short pitch winding. Disclosed therein is a high phase order alternating current rotating machine having an inverter drive that provides more than three phases of drive waveform of harmonic order H, and characterized in that the windings of the machine have a pitch of less than 180 rotational degrees. Preferably the windings are connected together in a mesh, star or delta connection. The disclosure is further directed to selection of a winding pitch that yields a different chording factor for different harmonics. The aim is to select a chording factor that is optimal for the desired harmonics.
In WO2006/065988, Edelson discloses a motor-generator machine comprising stator coils wound around the inside and outside of a stator, that is, toroidally wound. The machine may be used with a dual rotor combination, so that both the inside and outside of the stator may be active. Even order drive harmonics may be used, if the pitch factor for the windings permits them. In a preferred embodiment, each of the coils is driven by a unique, dedicated drive phase. However, if a number of coils have the same phase angle as one another, and are positioned on the stator in different poles, these may alternatively be connected together to be driven by the same drive phase. In a preferred embodiment, the coils are connected to be able to operate with 2 poles, or four poles, under H=1 where H is the harmonic order of the drive waveform. The coils may be connected together in series, parallel, or anti-parallel.
In U.S. Patent Appl. Pub. No. 2006/0273686, a motor-generator machine is disclosed comprising a polyphase electric motor which is preferably connected to drive systems via mesh connections to provide variable V/Hz ratios. The motor-generator machine disclosed therein comprises an axle; a hub rotatably mounted on said axle; an electrical induction motor comprising a rotor and a stator; and an inverter electrically connected to said stator; wherein one of said rotor or stator is attached to said hub and the other of said rotor or stator is attached to said axle. Such a machine may be located inside a vehicle drive wheel, and allows a drive motor to provide the necessary torque with reasonable system mass.
WO2006/113121 discloses a motor-generator machine comprising an induction and switched reluctance motor designed to operate as a reluctance machine at low speeds and an inductance machine at high speeds. The motor drive provides more than three different phases and is capable of synthesizing different harmonics. As an example, the motor may be wound with seven different phases, and the drive may be capable of supplying fundamental, third and fifth harmonic. The stator windings are preferably connected with a mesh connection. The system is particularly suitable for a high phase order induction machine drive systems of the type disclosed in U.S. Pat. Nos. 6,657,334 and 6,831,430. The rotor, in combination with the stator, is designed with a particular structure that reacts to a magnetic field configuration generated by one drive waveform harmonic. The reaction to this harmonic by the rotor structure produces a reluctance torque that rotates the rotor. For a different harmonic drive waveform, a different magnetic field configuration is produced, for which the rotor structure defines that substantially negligible reluctance torque is produced. However, this magnetic field configuration induces substantial rotor currents in the rotor windings, and the currents produce induction based torque to rotate the rotor.
Apparatus which enables a person to use a part or the whole of his body to control video games are known in the art.
U.S. Pat. No. 4,925,189 to Braeunig discloses a body-mounted video gaming exercise device which attaches to a user's upper body via straps and buckles. The user tilts the body to simulate movement of joystick and operate the game.
NZ537761 to James-Herbert discloses an improved computer game controller comprising a chair in a harness, in which a computer game player sits to control an avatar or the like in a computer game. By moving the chair, a joystick attached to the chair is moved, and thus the avatar is controlled by the game player's bodily movements.
U.S. Pat. No. 5,139,261 to Renato discloses a foot actuated computer game controller serving as a joystick. Pressure sensor units placed on floor are actuated by stepping on with a foot to control the game.
U.S. Pat. Nos. 7,226,018 and 7,237,748 disclose aircraft landing gear comprised of a wheel hub motor/generator disks stack, including alternating rotor and stator disks mounted with respect to the wheel support and wheel. The invention can provide motive force to the wheel when electrical power is applied, e.g. prior to touch-down. After touchdown the wheel hub motor/generator may be used as a generator thus applying a regenerative braking force and/or a motorized braking action to the wheel. The energy generated upon landing may be dissipated through a resistor and/or stored for later use in providing a source for motive power to the aircraft wheels for taxiing and ground maneuvers of the aircraft.
U.S. Patent Appl. Pub. No. 2006/0065779 discloses a powered nose aircraft wheel system for an aircraft which includes landing gear that extends from the aircraft. A wheel axel is coupled to the landing gear. A wheel is coupled to the wheel axel. A wheel motor is coupled to the wheel axel and the wheel. A controller is coupled to the wheel motor and rotates the wheel. A method of taxiing an aircraft includes permitting the wheel of the aircraft to freely spin during the landing of the aircraft. Power is transferred from an auxiliary power unit of the aircraft to the wheel motor. The wheel is rotated via the wheel motor. The aircraft is steered and the speed of the wheel is controlled via one or more controllers selected from an onboard controller and an offboard controller.